<!DOCTYPE html>
<html lang="zh">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>盒模型-阴影</title>
  <style>
    div {
      margin: 50px 100px;
      width: 240px;
      height: 320px;
      background-color: #0ff;
      box-shadow: 4px 5px 10px 2px rgba(0, 125, 255, .3);
    }
  </style>
</head>

<body>
  <div></div>
</body>

</html>